Process for dedusting solids-containing hydrocarbon oils

ABSTRACT

A surface active agent characterized as an ethoxylated or propoxylated ester, or ester constituted of a 1,4 sorbitan skeleton to which at least one and up to three ethoxy, propoxy, or mixed ethoxy-propoxy substitutent, and at least one fatty acid substitutent is attached through oxygen to the 2,3,5 and 6 carbon atoms. The surfactant is useful for removing very finely divided particulate solids from unconventional whole heavy petroleum crudes, heavy petroleum crude fractions, and residua, syncrudes and syncrude fractions, particularly shale oil and shale oil fractions, by the use of novel surface active agents.

BACKGROUND OF THE INVENTION AND PRIOR ART

The dwindling supplies of high grade petroleum feedstocks necessitatesthe increased production and processing of transportation fuels fromlower grade, heavy petroleum feedstocks and synthetic liquidhydrocarbons derived from hydrocarbon-containing, or precursorhydrocarbon-containing, solids. It has become necessary to process wholeheavy petroleum crudes and residua from unconventional sources, andsynthetic fuels (syncrudes; e.g. liquified coal, oil from coalcarbonization, oil from tar sands, shale oil and the like inclusive ofresidua or viscous syncrude fractions) are under active consideration ascommercial feedstock replacements for petroleum. Many of thehydrocarbons from these sources contain very fine particulate solids(e.g., sand, clays, oil shale, coal ash, carbonaceous particles and thelike) in concentrations which must be removed before such materials canbe employed as feedstocks in conventional refining operations.

The presence of the finely divided solids, particulates, or dusts, insuch liquids presents a major problem in processing hydrocarbons fromthese sources. For example, in shale oil, recovered from oil shale insitu or ex situ, extremely finely divided shale solids are concentratedin the shale oil, particularly in the heavy shale oil fractions. Thus,the oil produced by retorting oil shale is frequently contaminated withshale fines, the amount and characteristics of which may vary widely,and are a function of both the source of oil shale and the retortingprocess used. For example, oil produced from Colorado shale by a surfaceretorting process typically contains from about 2 to about 6 weightpercent of approximately 5 micron mean diameter relatively non-porousparticles. In contrast, oil produced from a surface retorted Australianshale typically contains from about 8 to about 16 weight percent ofapproximately 4 micron mean diameter particles, many of which are porousand some non-porous. Shale oils as a class present very difficult solidsseparation problems. Many shale oils contain non-porous solidscarbonates, and others contain porous clay based materials, or both. Theclay based solids may present added separation problems as contrastedwith those containing predominately carbonate solids, and such shaleoils often generally contain very high solids concentrations. Theconcentration of solids in such fractions often ranges as high as about8 percent or 10 percent, often even as high as 16 percent, and higher.These solids, major portions of which typically range in size from about0.5 micron to about 5 microns, often from about 1 micron to about 4microns, are extremely difficult to remove from the shale oil. Moreover,the shale oil contains high concentrations of olefinic compounds, thesereacting with one another or other compounds to form gums, or highmolecular weight polymers, this adding to the difficulty of separatingwater and solids from the shale oil. Such materials intefere withrefinery operations by clogging catalysts, coating process equipment,heat exchange surfaces, and the like. Conventional filtration andcentrifugation process per se are simply inadequate for dedusting, orremoving the gums and particulate solids from shale oil, or other typesof low grade heavy petroleum feedstocks and syncrudes, especially heavyoil fractions and residua. Equipment and processing costs arehorrendous, and loss of oil is one of the largest process debits. Wastedisposal problems created by the necessity of disposing of oil wetsolids adds to the burden.

It is conventional to "desalt" petroleum crudes to remove water andsalts. In a typical desalting process, a surface active agent and waterare often added to the petroleum crude, passed through a mixer to forman emulsion, and the emulsion then heated and passed to a desaltingvessel, or staged series of such vessels. In a desalting vessel,technically termed an electrostatic coalescer, the emulsion is subjectedto a high voltage electrostatic field to cause droplets of water tocoalesce and form separate phases; a water phase and a clean oil phaseseparated by an emulsion phase. A low salt, essentially water-free oilphase forms as an upper stratum, and a salt-containing aqueous phaseforms as a bottom stratum, with an emulsion phase located between theclean oil and water strata. The low salt, essentially water free (lowBS&W) oil phase is withdrawn from the top of the vessel for refineryprocessing, and the salt-containing aqueous phase is withdrawn from thebottom of the vessel and discharged as an effluent.

Solids have been removed from shale oil by the addition of water to theshale oil, and the mixture then subjected to an electrostatic field toresolve the mixture into a dedusted shale oil phase, and an aqueousphase which carries the finely divided solids. Reference is made, e.g.,to U.S. Pat. No. 3,951,771 which issued on Apr. 20, 1976 to E. D.Burger. In accordance with the Burger process an electrostatic coaleserand centrifuge are employed in combination to remove solids from shaleoil which contains low to moderate concentrations of solids. The solidscontent of the shale oil is reduced in the electrostatic coalescer, butthe oil losses present a serious problem. Reference is also made to U.S.Pat. No. 3,929,625 which issued Dec. 30, 1975 to Roy M. Lucas. Inaccordance with the process described by this reference, a surfaceactive agent and water are admixed with the oil to form an emulsion, andthe emulsion is then transferred to an electrostatic coalescer to form aseparate clean oil phase and a solids-containing aqueous phase, theformer of which is recovered as a feedstock for use in refineryoperations. A poly oxyalkylene derived nonionic polymeric surfactant isemployed as the surface active agent, exemplary of which areoxypropylated, oxyethylated, polyethylene amine and oxypropylated,oxyethylated butyl phenol formaldehyde resin. Solids removed from shaleoil by water washing/electrostatic coalescence, however, has not beenparticularly effective, and such treatment is particularly ineffectivewhen employed to dedust oils which contain about 6 weight percentsolids, or higher. Above this level of solids concentration phaseseparation within the electrostatic coalescer is not only difficult, butan unacceptably high level of oil is contained in the water effluent.Moreover, the solids content of the water effluent is sufficiently highthat flow is difficult due to the extremely high viscosity. Whereasdiluents, e.g., naphtha, diesel oil and the like, may be added to thecrude oils prior to treatment to reduce the total solids concentration,this necessitates an added step for recovery of the diluent which is aburden on the process.

It is, accordingly, the primary object of the present invention toobviate these and other prior art deficiencies, particularly byproviding novel compositions, and process for dedusting unconventionalwhole heavy petroleum crudes, heavy petroleum crude fractions andresidua, syncrudes, syncrude fractions, and syncrude residua.

A particular object is to provide novel compositions, and process fordedusting unconventional whole heavy petroleum crudes, heavy petroleumcrude fractions and residua, syncrudes and syncrude fraction whichcontains above about 6 weight percent finely divided solids, to providea clean oil product, or product suitable for use in refining operations.

A further, and more particular object is to provide novel compositionsuseful as additives in the dedusting of shale oil, and process whereinthe additive containing shale oil, particularly shale oil which containsabove about 6 weight percent finely divided solids, to provide a shaleoil effluent suitable for use in refining operations; the use of suchadditives, or process utilizing such additives, being particularlyuseful for dedusting a shale oil where it is desired to hydrogenate (orhydrogen treat) a feedstock constituting a major portion orsubstantially the whole shale oil, or high solids-containing bottomsfraction of the shale oil.

These objects and others are achieved in accordance with the presentinvention:

(I) A composition useful as a surfactant, which comprises

(A) an ethoxylated or propoxylated ester characterized as follows:##STR1## where R₁, R₂, R₃, and R₄ are selected from (a) ethoxy orpropoxy groups, or mixed ethoxy and propoxy groups, and

(b) the de-hydroxylated residue of a fatty acid molecule, or moietyrepresented by the formula ##STR2## where R is a straight-chainhydrocarbon moiety which can be substituted or unsubstituted, saturatedor unsaturated, and where unsaturated can contain conjugated orunconjugated double bonds. The hydrocarbon moiety can thus beexemplified by hydrocarbon groups which range from about 6 to about 30carbon atoms, preferably from about 8 to about 20 carbon atoms, e.g.,alkyl groups such as n-hexyl, n-octyl, n-decyl, n-dodecyl, n-octadecyl,octenyl, 9-octadecenyl, etc. This moiety can be further represented asthe de-hydroxylated residue of fatty acids such as caprylic, capric,lauric, myristic, eleostearic, licanic, arachidic, arochidonic, behenic,lignoceric, nisinic and the like.

In the formula, at least one and up to three of R₁, R₂, R₃, and R₄ isethoxy, propoxy or mixed ethoxy and propoxy groups, and conversely atleast one and up to three of R₁, R₂, R₃, and R₄ is the residue of afatty acid molecule, or moiety represented by the formula RCO--. Ethoxy,propoxy, or mixed ethoxy and propoxy groups, are thus attached throughoxygen to from one to three of the 2, 3, 5 or 6 carbon atoms of the 1,4-sorbitan skeleton, and from one to three of the fatty acid chains areattached through oxygen to the 2, 3, 5 or 6 carbon atoms of the 1,4-sorbitan skeleton. In other words, all of the R₁, R₂, R₃ and R₄substitutents attached through oxygen to the 2, 3, 5 or 6 carbons atomsare either ethoxy, propoxy or mixed ethoxy/propoxy groups or RCO-groups,and up to three of the substitutents can be ethoxy, propoxy or mixedethoxy/propoxy groups with the remainder RCO--, or up to three of thesubstitutents can be RCO-- with the remainder ethoxy, propoxy or mixedethoxy/propoxy groups. The fatty acid moiety is generally not a purespecies but comprised of mixtures of acid moieties. The molecularspecies is thus not a pure compound, but an admixture of compounds.Within the admixture of compounds, the molecular average of theadmixture, or average molecule, preferably contains about three of theethoxy, propoxy or mixed ethoxy/propoxy chains, and about one fatty acidchain. In an individual R₁, R₂, R₃ or R₄ group, where from one to threeof R₁, R₂, R₃ and R₄ are ethoxy, propoxy or mixed ethoxy and propoxygroups, the number of ethoxy, propoxy or mixed ethoxy/propoxy groups canrange from 1 to about 50, preferably from about 1 to about 25, and morepreferably from about 2 to about 10, and the sum total of the ethoxy,propoxy or mixed ethoxy/propoxy groups in the molecule ranges from about5 to about 50, preferably from about 10 to about 30. The end of themolecule which contains the 1, 4-sorbitan skeleton tends to be watersoluble, and the end of the molecule which contains the fatty acid chaintends to be water insoluble. In use, the solids particles in an oil arewater wet, and encapsulated by the action of the surfactant, the waterdroplets being coalesced into larger droplets which settle out with thesolids particles.

The surfactant is preferably constituted of an admixture of saidethoxylated or propoxylated ester and a second component, and mostpreferably said second component and a third component. The secondcomponent of the surfactant is characterized as

(B) an organo, hydrocarbyl, or aromatic monosulfonic acid, or admixtureof such acids, having the formula ##STR3## wherein R₅ is organo, ahydrocarbyl radical, or hydrocarbon radical selected from the groupconsisting of alkyl, aralkyl, cycloalkyl, aryl, alkaryl, alkenyl, andalkynyl including such radicals when inertly substituted. Thehydrocarbon moiety is exemplified by hydrocarbon groups which range fromabout one to about 30 carbon atoms, preferably from about one to about20 carbon atoms. When R₅ is alkyl, it can typically be methyl, ethyl,n-propyl, iso-propyl, n-butyl, i-butyl, sec-butyl, amyl, octyl, decyl,octadecyl, or the like. When R₅ is aralkyl it can typically be benzyl,betaphenylethyl, and the like. When R₅ is cycloalkyl, it can typicallybe cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl,2-methyl-cycloheptyl, 3-butyl cyclohexyl, 3-methyl cyclohexyl, and thelike. When R₅ is aryl, it can typically be phenyl, naphethyl, and thelike. When R₅ is alkaryl, it can typically be tolyl, xylyl, and thelike. When R₅ is alkenyl, it can typically be vinyl, allyl, 1-butenyl,and the like. When R is alkynyl, it can typically be ethynyl, propynyl,butynyl, and the like. R₅ can be inertly substituted, i.e., bear anon-reactive substitutent such as alkyl, aryl, cycloalkyl, ether,halogen, nitro, etc. The benzene ring can also be further inertlysubstituted. Typically inertly substituted R₅ groups and ringsubstitutents may include 3-chloropropyl, 2-ethoxyethyl,carboethoxy-methnyl, 4-methyl cyclohexyl, p-chlorophenyl, p-chlorobenzyl, 3-chloro-5-methylphenyl, etc. The preferred R₅ groups are alkyl,polyalkyl, aryl, polyaryl, alkoxy, polyalkoxy, arylalkyl, or alkylarylhydrocarbon radicals having from about 4 to about 18 carbon atoms,preferably from about 12 to about 15 carbon atoms. Preferably thesubstitutent hydrocarbon group is saturated or unsaturated,straight-chain or branched-chain, e.g., n-butyl, isobutyl, n-pentyl,isopentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, isobutyl,n-nonyl, tripropylene, n-decyl, undecyl, n-dodecyl, tridecyl,n-tetradecyl, pentadecyl, n-hexadecyl, n-octadecyl, eicosyl, docosyl,vinyl, propenyl, octenyl, 10-undecenyl, 9 octadecenyl, cyclopentyl,cyclohexyl, cyclohexamethyl, and the like; and R₅ is in an ortho or paraposition on the benzene nucleus relative to the sulfonic acid group.

Compounds of this class include, for example, aromatic monosulfonicacids wherein the benzene ring is substituted with up to five organic,or hydrocarboyl radicals, i.e., alkyl, polyalkyl, alkoxy, alkyl thio,and polyalkoxy ether radicals and the like.

Specific examples of sulfonic acids of this type include the alkyl orpolyalkyl substituted benzene sulfonic acid, and alkyl substitutedphenol sulfonic acid such as dodecyl benzene sulfonic acid, kerylbenzene sulfonic acid, nonylbenzene sulfonic acid, dinonyl benzenesulfonic acid, trihexyl benzene sulfonic acid, nonyl phenol sulfonicacid, tetradecyl benzene sulfonic acid, and the like.

The admixture, as suggested, most preferably also includes a thirdcomponent, or mixture of such components, viz.,

(C) an ammonium ion, substituted ammonium ion or alkali metalsubstituted organo, hydrocarbyl, or aromatic monosulfonic acid, i.e., anammonium ion, substituted ammonium ion or alkali metal sulfonatecharacterized by the formula ##STR4## wherein M is an ammonium ion,substituted ammonium ion or metal selected from Group I-A of thePeriodic Table of the Elements (E. H. Sargent & Co. ScientificLaboratory Equipment, Copyright 1962), preferably sodium, and

R₆ is organo, a hydrocarbyl radical, or hydrocarbon radical selectedfrom the group consisting or alkyl, aralkyl, cycloalkyl, aryl, alkaryl,alkenyl, and alkynyl including such radicals when inertly substituted.The hydrocarbon moiety is exemplified by hydrocarbon groups which rangefrom about one to about 30 carbon atoms, preferably from about one toabout 20 carbon atoms. When R₆ is alkyl, and can typically be methyl,ethyl, n-propyl, iso-propyl, n-butyl, i-butyl, sec-butyl, amyl, octyl,decyl, octadecyl, and the like. When R₆ is aralkyl it can typically bebenzyl, betaphenylethyl, and the like. When R₆ is cycloalkyl, it cantypically be cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl,2-methyl-cycloheptyl, 3-butyl cyclohexyl, 3-methyl cyclohexyl, and thelike. When R₆ is aryl, it can typically be phenyl, naphethyl, and thelike. When R₆ is alkaryl, it can typically be tolyl, xylyl, or the like.When R₆ is alkenyl, it can typically be vinyl, allyl, 1-butenyl, and thelike. When R₆ is alkynyl, it can typically be ethynyl, propynyl,butynyl, and the like. R₆ can be inertly substituted, i.e., bear anon-reactive substitutent such as alkyl, aryl, cycloalkyl, ether,halogen, nitro, etc. The benzene ring can also be further inertlysubstituted. Typically inertly substituted R₆ groups may include3-chloropropyl, 2-ethoxyethyl, carboethoxymethnyl, 4-methyl cyclohexyl,p-chlorophenyl, p-chloro benzyl, 3-chloro-5-methylphenyl, etc. Thepreferred R₆ groups are alkyl, polyalkyl, aryl, polyaryl, alkoxy,polyalkoxy, arylalkyl or alkylaryl hydrocarbon radicals having fromabout 4 to about 18 carbon atoms, preferably from about 12 to about 15carbon atoms. Preferably the substitutent hydrocarbon group is saturatedor unsaturated, straight-chains or branched-chains, e.g., n-butyl,isobutyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, n-octyl, isooctyl,2-ethylhexyl, isobutyl, n-nonyl, tripropylene, n-decyl, undecyl,n-dodecyl, tridecyl, n-tetradecyl, pentadecyl, n-hexadecyl, n-octadecyl,eicosyl, docosyl, vinyl, propenyl, octenyl, 10-undecenyl, 9 octadecenyl,cyclopentyl, cyclohexyl, cyclohexamethyl, and the like; and the R₆ in anortho or para position on the benzene nucleus relative to the ammoniumion, substituted ammonium ion, or metal sulfonate group.

Exemplary of suitable ammonium or alkali metal sulfonates are theammonium, sodium, or potassium salts of aromatic monosulfonic acidswherein the benzene ring is substituted with up to five organic, orhydrocarboyl radicals, e.g., alkyl, polyalkyl, alkoxy, alkyl thio,polyalkoxy ether radicals and the like.

Specific examples of sulfonic acid salts of this type include theammonium or substituted ammonium salt of the alkyl or polyalkyl benzenesulfonic acid, i.e., ammonium dodecylbenzene sulfonate, triethanolaminedodecylbenzenesulfonate, sodium salt of the alkyl or polyalkyl benzenesulfonic acid, such as the sodium salt of dodecyl benzene sulfonic acid,the sodium salt of keryl benzene sulfonic acid, the sodium salt ofdinonyl benzene sulfonic acid, the sodium or potassium salt of trihexylbenzene sulfonic acid, the sodium or potassium salt of nonyl phenolsulfonic acid, the sodium or potassium salt of tetradecyl benzenesulfonic acid, and the like.

In its most preferred aspects the composition of this invention includesnot only the surfactant characterized in I(A), preferably I(A)+I(B), ormore preferably I(A)+I(B)+I(C), but also the additional presence of anoil soluble demulsifier.

(II) The demulsifier is constituted of

an ethoxylated or propoxylated, or admixed ethoxylated/propoxylated,phenol formaldehyde resin substituted at a position para to the ethoxyor propoxy group, or mixed ethoxy/propoxy groups, by an organo,hydrocarbyl of hydrocarbon group, said modified phenol formaldehyderesin being characterized as follows: ##STR5## wherein R₇ represents oneor more ethoxy or propoxy groups, or mixed ethoxy and propoxy groups,and

R₈ is a hydrocarbyl radical, or hydrocarbon radical selected from thegroup consisting of alkyl, aralkyl, cycloalkyl, aryl, alkaryl, alkenyl,and alkynyl including such radicals when inertly substituted. Thehydrocarbon moiety is exemplified by hydrocarbon groups which range fromabout one to about 30 carbon atoms, preferably from about one to about20 carbon atoms. When R₈ is alkyl, R₈ can typically be methyl, ethyl,n-propyl, iso-propyl, n-butyl, i-butyl, sec-butyl, amyl, octyl, decyl,octadecyl, and the like. When R₈ is aralkyl it can typically be benzyl,betaphenylethyl, and the like. When R₈ is cycloalkyl, it can typicallybe cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl,2-methyl-cycloheptyl, 3butyl cyclohexyl, 3-methyl cyclohexyl, and thelike. When R₈ is aryl, it can typically be phenyl, ethylphenyl, and thelike. When R₈ is alkaryl, it can typically be tolyl, xylyl, and thelike. When R₈ is alkenyl, it can typically be vinyl, allyl, 1-butenyl,and the like. When R₈ is alkynyl, it can typically be ethynyl, propynyl,butynyl, and the like. R₈ can be inertly substituted, i.e., it may beara non-reactive substitutent such as alkyl, aryl, cycloalkyl, ether,halogen, nitro, and the like. Typically inertly substituted R₈ groupsmay include 3-chloropropyl, 2-ethoxyethyl, carboethoxymethnyl, 4-methylcyclohexyl, p-chlorophenyl, p-chloro benzyl, 3-chloro-5-methylphenyl,etc. In the formula, m is an integer of 1 or greater than 1, and themolecular weight of the demulsifier, or resin, generally ranges fromabout 2000 to about 20,000, preferably from about 5000 to about 10,000.The resin can be unmodified, or modified as by substitution or additionof substitutents in the side chains or nucleus of the aromaticconstitutents of the molecules, especially by reaction at one or bothterminal nuclei.

The compounds per se characterized as I(B), I(C) and II are known. Thefatty acid esters characterized as I(A) are prepared by directesterification of 1,4-sorbitan. In the preparation of the fatty acidesters a preselected amount of the fatty acid is charged into a reactionvessel and admixed with incremental charges of the ethylene or propyleneoxide, or both, at controlled temperature and pressure untilsubstantially equivalent molar amounts of the two reactants have beenreacted, and reaction is complete. For example, 4000 pounds of sorbitanmonooleate is charged into a stainless steel vessel and admixedinitially with 30 pounds of ethylene oxide, the reaction mixture beingvented, purged of air and stirred while controlling the temperaturebelow about 275° F. and pressure of about 0-15 psig. While controllingthe temperature and pressure at these conditions, increments of theethylene oxide are continuously added until the reaction is complete.Thus, a charge of ethylene oxide in the amounts of 5000 pounds and 4460pounds, respectively, are placed in weigh tanks and, while controllingthe temperature of between about 270°-275° F., the ethylene oxide ischarged to the stirred reaction vessel at a rate of about 2 gallons perminute. As the temperature and pressure subside, the rate of addition ofethylene oxide is increased to about 4 gallons per minute. When reactionhas been completed, and all of the ethylene oxide has been added, thereaction vessel is purged with nitrogen, and thereafter the reactionmixture is neutralized with sodium hydroxide, and the fatty acid esterseparated from the reaction mixture.

The surfactant and demulsifier are prepared prior to use by dissolvingone or both ingredients in an oil soluble solvent, and preferably eachis separately dissolved in an oil soluble solvent and thesolvent-containing additives blended together at the time they are addedto the oil. Exemplary of oil soluble solvents for dissolving theseadditives are aromatic hydrocarbons having a single benzene nucleus,preferably aromatic hydrocarbons containing from 6 to about 9 carbonatoms, e.g., xylene, n-propyl benzene, isopropyl benzene and the like;cycloparaffin hydrocarbons which contain from 4 to about 9 carbon atoms,e.g., cyclobutane, cyclopentane, cyclohexane, cycloheptane and the like;water soluble alcohols such as propyl alcohol, isopropyl alcohol,isobutyl alcohol, sec-butyl alcohol, t-butyl alcohol and the like;aromatic alcohols such as triphenylcarbinol and the like; water solublepolyhydric alcohols such as ethylene glycol, hexamethylene glycol,glycerol and the like; or admixtures of these and/or other solvents.

The invention resides in the discovery of novel surfactants, andparticularly novel admixtures of surfactants and demulsifiers forremoving very finely divided particulate solids from solids-containingpetroleum and syncrudes. Generally, the surfactant and demulsifier priorto use are each dissolved in a suitable solvent and each separatelyadded, or blended together and then added, to the solids-containingwhole heavy crude petroleum or syncrude, or petroleum or syncrudefraction at the site wherein the solids are to be removed from the oil.The surfactant and demulsifier are added, with water, to thesolid-containing oil in concentrations adequate to remove the solidsfrom the oil, and concentrate the solids within the water phase.Suitably, the surfactant, or surfactants, and the demulsifier, ordemulsifiers, are added to the oil in concentration ranging from about10 parts to about 5000 parts, preferably from about 30 parts to about 80parts, per million parts by volume of oil (vppm). The ratio ofdemulsifier:subfactant generally ranges from about 1:1 to about 15:1,preferably from about 2:1 to about 4:1, based on the sum total volume ofthe surfactant and demulsifier.

It is required to form an emulsion between the two immiscible liquids,which creates a large interfacial area between the oil and water phases.The principles for the formation of oil and water emulsions ae wellknown. The addition of a surfactant into an oil significantly lowers theinterfacial tension of the oil against water due to the concentration ofthe surfactant at the oil/water interface and promotes emulsificationbetween the oil and water faces. On the other hand, a demulsifier, atleast to an extent, breaks the oil/water emulsion by removing the oilfilm from around the solids particles, and cleans the water phase ofoil. In the instant situation, the surfactant of this invention cleansthe surfaces of the solids of oil and aids in the transfer of solids tothe water phase. The demulsifier causes the small water droplets tocoalesce, and at the same time cleans, or purges, the oil from the waterphase. The surfactant is, in fact, outstanding in its effectiveness inwetting the solids, and cleaning the surfaces of the solids of oil, andthe demulsifier is similarly effective in breaking the oil and wateremulsion, and in removing and transferring oil from the water phase tothe oil phase. The wetted solids are readily transferred from the oilphase to the water phase.

Water is added to the oil containing the surfactant and demulsifier,generally in concentration ranging from about 5 percent to about 50percent, preferably from about 10 percent to about 30 percent, based onthe volume of the oil. The oil and water are then emulsified, as byshearing the oil and water in a mixer. The contacting water, in thepresence of the surfactant water wets and cleans the solids particlesand transfers the solids to the water phase. The action of thedemulsifier causes the small drops of water to coalesce and cleans theoil from the water phase. Upon gravity settling, preferably at elevatedtemperature which is helpful in breaking the emulsion, thesolids-containing water phase cleanly separates from the oil phase. In apreferred embodiment, however, the oil and water emulsion istransported, or flowed, into an electrostatic coaleser to form a cleanoil phase overflow and solids-containing water phase underflow; or wherethe whole heavy crude petroleum or syncrude oil, or petroleum orsyncrude fraction contains a particularly high concentration of solids,the oil and water emulsion can be treated initially by gravity settlingto effect partial separation of a solids-containing water phase, and theremaining emulsion and/or oil phases further treated in an electrostaticcoalescer, or staged series of electrostatic coalescers.

In accordance with the best mode of practicing the process, two schemesof operation are generally employed depending upon the nature andconcentration of solids contained in the oil. A first process schemeembodies treatment of an oil which contains a low to moderate amount ofsolids, e.g. about 2 to 6 percent solids, and a second embodiestreatment of an oil which contains moderate to high concentrations ofsolids, e.g. about 6 to 16 percent solids.

In the drawings:

FIG. 1 schematically depicts a continuous process for treating an oil,typically a shale oil, which contains a low to moderate amount of shalesolids; and

FIG. 2 schematically depicts a continuous process for treating an oil,typically a shale oil, which contains moderate to high amounts ofsolids.

With reference to FIG. 1, shale oil is received from a source, e.g., astorage tank 0. The oil contains a low to moderate level of solids, muchof which is perhaps non-porous solids. An admixture of surfactant anddemulsifier is added directly to the oil downstream of the point whereit is withdrawn from storage tank 0, i.e., via line 1. In treating anoil which contains low to moderate amounts of solids, generally fromabout 20 parts to about 300 parts, preferably from about 20 parts toabout 100 parts, per million parts by volume (vppm) of oil, of thesurfactant and demulsifier are added. A washwater is then added to theoil upstream of heat exchanger 3 as via line 4. The whole of therequired amount of washwater can be added at this point, or part of thewashwater can be added at this point and additional water addeddownstream of the heat exchanger 3 as via line 5.

In the practice of the process, generally the whole of the requiredamount of surfactant and demulsifier are added upstream of heatexchanger 3. Generally, from about 5 percent to about 90 percent,preferably from about 30 percent to about 60 percent, of the requiredwashwater is added as primary washwater upstream of the heat exchanger 3and the balance of the washwater, or secondary washwater, is addeddownstream of the heat exchanger 3. The heat transmitted through theheat exchanger 3 is sufficient to raise the temperature of the primarywater, additives and oil passed therethrough to from about 100° F. toabout 350° F., preferably from about 200° F. to about 280° F. Additionof primary washwater is essential to suppress the formation of deposits,scale and other forms of encrustation, on heat exchanger surfaces. Thewater, additives and oil must be thoroughly admixed to form an emulsion,and hence can be next passed through a mixer, e.g., a mix valve 6 andsheared to form an emulsion. A differential pressure of from about 3pounds per square inch (psi) to about 30 psi, preferably from about 5psi to about 15 psi is maintained across the mix valve 6. A globe valveis generally a suitable type of mixer for this purpose; though variousother types of mixing devices can be employed, e.g., in-line dynamicmixers, centrifugal pumps and the like. The emulsion is then passed intoan electrostatic coalescer 7, or series of staged electrostaticcoalescers (not shown). [Elelcto-static coalescers of suitable type aredescribed, e.g., in "Chemical Engineering Progress" vol. 61, no. 10,October 1965, at Pages 51-57 in an article by Logan C. Waterman.Commercial units are available from Petrolite Corporation and HoweBaker.] The temperature of the oil and water emulsion within theelectrostatic coalescer 7 ranges from about 100° F. to about 350° F.,preferably from about 200° F. to about 280° F., and the residence timeof the emulsion, oil and water phases within the electrostatic coalescer7 ranges from about 10 minutes to about 80 minutes, preferably fromabout 20 minutes to about 60 minutes. Within the electrostatic coalescer7 the emulsion is separated into a clean oil phase which is removed asan overflow from the vessel via line 8, and a solids-containing waterphase which is removed as an underflow from the vessel via line 9.

Reference is now made to FIG. 2, this figure showing a preferred type offacility for treating a moderate to high solids-containing shale oil,suitably one which may contain both porous and non-porous solids. Thisfacility provides for an initial treatment of the oil in one or aplurality of stages, preferably the latter, notably within settlingtanks (or vessels which are the equivilent of settling tanks) to removea major portion of the solids, and thereafter the remainder of thesolids are removed from the oil generally as described by reference tothe proceeding figure.

In accordance with this process, oil is withdrawn via line 5 from asuitable source, suitably a storage tank O, and the surfactant anddemulsifier are added to the oil as via line 6 and admixed with the oilby passage through a suitable mixer 7. Water is added to line 5downstream of mixer 7 via line 8. The sum total of the additive, waterand oil are then passed through mixer 9, emulsified, and then introducedinto vessel 10 via line 11. The surfactant and demulsifier generally areadded in concentrations ranging from about 100 vppm to about 3000 vppm,preferably from about 500 vppm to about 2000 vppm, and the temperatureof the contents of the tank is maintained at from about ambient to about200° F., preferably from about 150° F. to about 180° F. An oil phaseoverflow is withdrawn via line 12 from the top of the vessel 10 aftersettling, and it is passed via line 12 through heat exchanger 16. Awater phase underflow, which contains a preponderance of solids, iswithdrawn from vessel 10 and optionally passed via line 13 to the secondvessel 20, and if desired additional fresh water and additive can beadmixed with the water, as via line 4, and the admixture of additive andwater then fed through mixer 3 into vessel 20. Optionally, some of theemulsion can be withdrawn via valved line 9 and also passed via line 13to vessel 20. An oil effluent is removed from vessel 20 via line 14, andcombined with the oil effluent in line 12 from vessel 10. Asolids-containing water stream is removed from vessel 20 via line 15.The oil effluent from lines 12, 14 is then treated as described in theprocess described by reference to FIG. 1.

The oil, partially denuded of solids by treatment in vessels 10, 20, isthen admixed with additional water introduced on the upstream side ofheat exchanger 16 via line 17, with secondary water being added via line18 on the downstream side of the heat exchanger, if desired. Aspreviously suggested, the oil, water and additive is passed through heatexchanger 16 and heated sufficiently to raise the temperature of theoil, water and additive from about 100° F. to about 350° F., preferablyfrom about 200° F. to about 280° F. The admixture is then sheared oremulsified in mixer 19. Suitably, the admixer 19 is a mix valve and theadmixture is sheared at differential pressures ranging from about 3 psito about 30 psi, preferably from about 5 psi to about 15 psi, to form anemulsion. The emulsion is then fed into an electrostatic coalescer 30,or series of electrostatic coalescers, the emulsion, oil and waterphases being maintained in said electrostatic coalescer 30 for a timesufficient to provide a residence time ranging from about 10 minutes toabout 80 minutes, preferably from about 20 minutes to about 60 minutes,and at a temperature ranging from about 100° F. to about 350° F.,preferably from about 200° F. to about 280° F. A clean oil overflow isremoved from the top of the electrostatic coalescer 30 via line 21 whilea solids-containing aqueous stream underflow is removed fromelectrostatic coalescer 30 via line 22.

The following examples, and comparative demonstrations, are furtherexemplary, particularly to the high effectiveness of the novel additivesof this invention, and process, in removing solids from whole heavycrude petroleum and syncrudes, and fractions and residua thereof. In theexamples and demonstrations, all parts are in terms of weight unitsexcept as otherwise specified, residence times in terms of minutes, andtemmperatures in terms of degrees Farhenheit.

Examples 1-6 describe a continuous process for treating a while shaleoil which contains a low to moderate amount of solids, such as would beobtained from a commercial surface retorting plant operation. Shale oilfractions, and a shale oil diluent obtained from a pilot plant operationwere blended together to simulate a commercial whole shale oil feed.

EXAMPLES 1-6

In conducting a series of treatments to demonstrate the effectiveness ofthe process in removing solids particles from a commercially producedraw Colorado shale oil via the procedure generally described byreference to FIG. 1, a solids-containing Parachute Creek, Green RiverBasin surface retorted raw shale oil (obtained from Mahogany Zoneprecursor shale) was employed. A shale oil was obtained from a pilotplant which recovered a liquid product from the surface retorted shalein three separate fractions, a bottom oil, a distillate, and a naphtha;the three fractions being combined to provide a "whole oil". Theinspections (solids free basis) on the raw whole oil are given in TableI-A. Since, however, the pilot plant did not achieve completecondensation of light oil components, the pilot plant whole oil washeavier than that estimated for a more efficient commercial plant.Therefore, by combining the assays of liquid and vapor streams from thepilot plant, a total liquid product characteristic of that which wouldbe expected from a commercial plant was obtained as shown in Table I-B.A commercial liquid produt would thus be expected to have a density of27 °API as contrasted with the heavier 20.6 °API of the pilot plant"whole oil". Raw liquid shale oil for studying the effect of oil densityto simulate commercial operations was thus prepared by adding additionalamounts of the distillate or naphtha fractions to the "whole oil,"inspections for the distillate and naphtha being given in Tables I-C andI-D, respectively.

                  TABLE I-A                                                       ______________________________________                                        Pilot Plant "Whole Oil"                                                       ______________________________________                                        Gravity, °API                                                                           20.6                                                         VIS @ 100° F.                                                                           22.0                                                         15/5 Distillation                                                             IBP                 -- °F.                                               5%             230                                                          10               310                                                          20               440                                                          30               560                                                          40               650                                                          50               740                                                          60               830                                                          70               940                                                          80               1030                                                         ______________________________________                                    

                  TABLE I-B                                                       ______________________________________                                        Anticipated Total Liquid Product From                                         Commercial Retorting Plant, Colorado Shale                                    (computer generated from assays of liquid and                                 vapor streams from pilot plant)                                               C.sub.5.sup.+  Fractions                                                      Boiling Point   Gravity  Volume                                               Range °F.                                                                              °API                                                                            %                                                    ______________________________________                                         75-100         83.0     3.6                                                  100-200         66.7     4.5                                                  200-300         55.1     6.8                                                  300-400         44.8     7.2                                                  400-500         36.9     6.4                                                  500-600         29.1     8.2                                                  600-700         23.2     9.1                                                  700-800         19.5     11.5                                                 800-900         16.7     11.5                                                  900-1000       13.8     11.2                                                 1000-1100       10.4     7.7                                                  1100-1200       6.3      6.3                                                  1200+           2.6      6.0                                                  Total           27.0     100.0                                                ______________________________________                                    

                  TABLE I-C                                                       ______________________________________                                        Pilot Plant Distillate                                                        Gravity 27.9 °API                                                      D86 Distillation   Vac Distillation                                           ______________________________________                                        IBP         181° F.                                                                             5%       144° F.                              10  5%   219           10      174                                            10       323           20      212                                            20       367           30      237                                            30       395           40      264                                            40       433           50      296                                            50       468           60      338                                            60       507           70      435                                            70       566           80      595                                            80       641           87      714                                                     cracked               cracked                                        ______________________________________                                    

                  TABLE I-D                                                       ______________________________________                                        Pilot Plant Naphtha                                                           ______________________________________                                        Gravity 47.1 °API                                                      84.8% C        vis @ 40° C. 1.3 cs                                     12.9% H                                                                       0.88% S                                                                       0.72% O                                                                        0.7% N                                                                       D86 Distillation                                                              IBP               119° F.                                                5%           160                                                            10             176                                                            20             203                                                            30             230                                                            40             260                                                            50             292                                                            60             328                                                            70             388                                                            80             449                                                            90             550                                                            FBP            614                                                            ______________________________________                                    

The whole oil was added to, and then withdrawn as needed from a storagetank, blended with diluent, and used in a series of tests as describedby reference to Table I-E. The portions of raw shale oil were blendedwith water and an admixture of a surfactant and demulsifier and fedthrough a heat exchanger to heat the admixture to the operatingtemperature of the electrostatic coalescer, or electrostatic coalescers,as described by reference to FIG. 1. The specific surfactant anddemulsifier used in the series of tests described by reference to TableI-E, inclusive of non-active ingredients, are identified as follows:

Surfactant

Ethylene glycol mono-butyl ether 5.03%, 20 mole E.O. (ethylene oxide) onsorbitan mono-oleate 35.35%; water 0.51%; sodium sulfate 0.12%; dodecylbenzene sulfonic acid 4.88%; H₂ SO4 in inert oil 0.07%; water 0.03%;total water in product=0.54%; sodium sulphonate (in mineral oil) 2.52%;Aromatic Naphtha 48.4%; mineral oil 1.45%; isopropyl alcohol 1.50%.

Demulsifier

Heavy Aromatic Naphtha 61.00%, Ethoxylated p-nonyl Phenol FormaldehydeResin 19.93%, Ethylene Glycol Mono-butyl Ether 9.85%, Oxyalkylatedp-nonyl Phenol Formaldehyde Resin 5.02%, Xylene 3.5%, SodiumNaphthenate, 0.57%, Naphthenic Acid 0.06%, Sodium DodecylbenzeneSulfonate 0.03%, and H₂ O 0.04%.

The diluted whole oil/water admixtures were then fed through a mixingvalve of the needle type and emulsified. The amounts of surfactant anddemulsifier used, the amount of dilution of the whole oil with thediluent, the identity of the diluent, the gravity of the resultant rawshale oil, the amount of washwater used, and the differential pressureapplied across the mixing valve are given in Table I-E for six series ofruns. The emulsions were then fed into an electrostatic coalescer, or aseries of two staged Howe Baker electrostatic coalescers, ofconventional design. An alternating current field was employed at apotential of 4000 volts, with an electrode spacing of 3 inches. Thesetreatments, as described in Table I-E, demonstrated excellent solidsremoval in Examples 1 and 2, even with oil gravities somewhat heavierthan the anticipated commercial product. The results obtained in Example3, which uses the heaviest oil feed, while somewhat less impressive waslikewise successful. In all three of these runs, essentially no oil waslost with the water.

Examples 4-6 exemplify a series of treatments wherein diluted whole oilwas treated as described with reference to Examples 1-3, and thereafteradditional water was added to the once dedusted shale oil, and the oncededusted shale oil again similarly treated. Additional surfactant anddemusifier were not added for the second treatment because sufficient ofthese agents were present in the once treated shale oil. The raw shaleoil used in this series had been stored under warm ambient temperatureconditions, and for this reason presented a more difficult solidsremoval operation. Nonetheless, operation in accordance with theconditions described by Examples 4, 5, and 6 show excellent solidsremoval. Oil carryunder again was nil.

                                      TABLE I-E                                   __________________________________________________________________________    Treatment of Shale Oil for Solids Removal                                                 Feed Oil                Oil Solids Content                                    Whale Oil          Mixing   From                                                                              From                                   Demulsifier/                                                                         Distillate                                                                          Gravity      Valve    First                                                                             Second                                 Surfactant                                                                           of Naphtha                                                                          (Solids Free)                                                                        Washwater                                                                           Pressure                                                                           In  Stage                                                                             Stage                                                                             Oil                           Example                                                                            ppm Each                                                                             vol/vol                                                                             °API                                                                          Vol % Drop psi                                                                           Wt. %                                                                             Wt %                                                                              Wt. %                                                                             Carryunder                    __________________________________________________________________________    Single Treatment                                                              1    60/15  50/50(1)                                                                            24     10    5    4.4 0.03                                                                              --  nil                           2    60/15  70/30(1)                                                                            23     10    5    2.8 0.03                                                                              --  nil                           3    60/15  90/10(1)                                                                            22     10    5    10.2                                                                              0.12                                                                              --  nil                           Two Treatments in Series                                                      4    120/30(3)                                                                            70/30(2)                                                                            26     10/5(4)                                                                             5(5) 2.9 0.12                                                                              0.07                                                                              nil                           5    120/30(3)                                                                            75/25(2)                                                                            25     10/5(4)                                                                             5(5) 2.9 0.27                                                                              0.07                                                                              nil                           6    120/30(3)                                                                            80/20(2)                                                                            24     10/5(4)                                                                             5(5) 3.9 0.30                                                                              0.10                                                                              nil                           __________________________________________________________________________     (1)Distillate as in Table IC.                                                 (2)Naphtha as in Table ID.                                                    (3)Added in first treatment only.                                             (4)10 vol. % water in first treatment, 5 vol. % water added in second         treatment.                                                                    (5)Each treatment.                                                       

EXAMPLES 7-9

A further series of runs were conducted with a solids containing surfaceretorted raw shale oil produced from a Kerosene Creek Seam Australianoil shale. The shale oil feeds used were produced from a blend of pilotplant products to provide a shale oil product substantially similar toan oil produced commercially. The liquid product from the pilot plantwas constituted of four fractions: heavy oil (H), middle oil (M), lightoil (L), and gas naphtha (N) fractions. The term "total oil" is appliedto the combined heavy, middle, and light oil fractions. The inspectionsfor the total oil product (H+M+L) are given in Table II-A, andinspections of the gas naphtha product are given in Table II-B.

                  TABLE II-A                                                      ______________________________________                                        Analyses of Total Oil Product.sup.(1)(2)                                      Run No.         7        8          9                                         ______________________________________                                        Mixing Ratio, Wt. %                                                           Heavy Oil       26.0     29.1       26.1                                      Middle Oil      19.1     27.1       29.3                                      Light Oil       54.9     43.8       44.6                                      Density, g/ml (15° C.)                                                 Heavy Oil       0.945    0.962      0.971                                     Middle Oil      0.924    0.907      0.914                                     Light Oil       0.835    0.839      0.841                                     Total Oil       0.875    0.886      0.889                                     Ultimate Analyses                                                             C, Wt. %        85.49    85.59      85.68                                     H, Wt. %        11.49    11.25      11.26                                     N, Wt. %        1.06     1.10       1.07                                      O, Wt. %        1.37     1.44       1.40                                      S, Wt. %        0.59     0.62       0.59                                      Density, g/ml (15° C.)                                                                 0.876    0.889      0.891                                     Viscosity, 10.sup.6 m.sup.2 /sec                                              20° C.   4.267    8.903      6.919                                     40° C.   2.733    4.846      3.625                                     50° C.   2.263    3.668      3.261                                     Pour Point, °C.                                                                        +18      +21        +18                                       Conradson Carbon, Wt. %                                                                       2.43     2.78       2.67                                      Moisture, Wt. % 0.117    0.086      0.079                                     Distillation, °C.                                                      IBP             24                  31                                         5%             95                  107                                       10              105                 133                                       20              154                 174                                       30              186                 205                                       40              222                 271                                       50              260                 306                                       60              304                 334                                       70              346                 403                                       80              443                 455                                       90              508                 --                                        FBP             520                 550                                       Residue, Vol. % 9                   13                                        ______________________________________                                         .sup.(1) Composite of heavy, middle and light oil in production ratio.        Dust free basis.                                                              .sup.(2) Associated gas naphtha product (Table IIB) is 0.124 weight           naphtha per weight total oil for run No. 7, 0.119 for run No. 8, and 0.13     for run No. 9. Combined total oil and gas naphtha constituted the produce     C.sub.5.sup.+  fraction.                                                 

                  TABLE II-B                                                      ______________________________________                                        Analyses of Gas Naphtha Product.sup.(1)                                       Run No.        7          8       9                                           ______________________________________                                        Density, g/ml (15° C.)                                                                0.706      0.714   0.716                                       Ultimate Analyses                                                             C, Wt. %       86.03      86.02   86.06                                       H, Wt. %       13.34      13.19   13.23                                       N, Wt. %       <0.20      <0.20   <0.20                                       O, Wt. %       0.23       0.41    0.38                                        S, Wt. %       0.35       0.33    0.28                                        Distillation, °C.                                                      IBP            27         29      28                                          10%            31         35      33                                          20             46         50      49                                          30             53         57      58                                          40             60         64      65                                          50             66         70      74                                          60             73         78      78                                          70             81         86      86                                          80             92         96      96                                          90             110        113     113                                         FBP            143        146     143                                         Residue, Vol. %                                                                              1          1       1                                           Loss, Vol. %   8          6.5     7.5                                         Bromine No., g/100 g              160                                         Acid No., mg KOH/g                0.23                                        Group Analysis                                                                Aromatics, Vol. %                 17.5                                        Olefins, Vol. %                                                                              68.5                                                           Saturates, Vol. %                 14.0                                        ______________________________________                                         .sup.(1) Water content of 200 to 600 ppm as determined by KarlFischer         method.                                                                  

A series of bottle tests were conducted using the product characterizedin Table II-A under Run 7 as feeds to demonstrate the effectiveness ofan admixture of the surfactant and demulsifier used in Examples 1-6 toproduce separation of the emulsified oil and transfer of the solids tothe oil phase, and removal of oil from the water phase, and to show theeffects of the feed oil composition (H+M+L). These tests, the results ofwhich are given in Table III, consisted of blending the various oilfractions from the retorting pilot plant at different pH levels, adding(for comparative purposes) no surfactant or demulsifier, adding either3000 ppm of an admixture of the disclosed surfactant and demulsifier,adding either 15 or 30 vol. % of water, mixing by hand shaking, andallowing the mixture to settle for 1.5 hour while maintaining atemperature of 150° F. At the end of the 1.5 hour settling period, eachof the bottles were visually examined for the separation of the waterphase from the oil phase and transfer of solids to the water phase. Theresults as given in Table III (Column 3) show the excellent resultsobtained when the disclosed admixture of surfactant and demulsifier isused in an oil corresponding to a whole liquid product which includes(H+L+M+N). The performance of the admixture of surfactant anddemulsifier, as will be observed, was excellent over a range of washwater pH values of 4 to 11. Laboratory tap water was used with pHadjustment by either HCl or NaOH addition.

                  TABLE III                                                       ______________________________________                                        Demonstration of Performance of                                               Admixtures of Surfactant and Demulsifier                                      in Bottle Tests                                                                            Oil Composition                                                                 Production Ratio                                                                           Production Ratio                                                 H + M + L    H + M + L + N                                     Treatment      4.6 Wt. % Solids                                                                           4.1 Wt. % Solids                                  ______________________________________                                        No surfactant or                                                              demulsifier plus                                                              15% water, pH 7                                                                              no oil/water no oil/water                                                     separation   separation                                        30% water, pH 7                                                                              no oil/water no oil/water                                                     separation   separation                                        Disclosed surfactant                                                          (1 part) and demulsifier                                                      (4 parts) plus                                                                15% water      no oil/water clean oil/water                                   pH 4           separation   separa., solids                                                               in water                                          pH 7           no oil/water clean oil/water                                                  separation   separa., solids                                                               in water                                          pH 11          no oil/water clean oil/water                                                  separation   separa., solids                                                               in water                                          30% water      no oil/water excellent oil/                                                   separation   water separation                                                              solids in water                                   pH 7           partial oil/water                                                                          excellent oil/                                                   separation   water separation                                                              solids in water                                   pH 11          no oil/water excellent oil/                                                   separation   water separation                                                              solids in water                                   ______________________________________                                    

In another test, the water washing/gravity settling step was alsodemonstrated on a complete liquid product oil sample (H, M, L, & N)characterized in Tables II-A and II-B under Run 8 containing 10.6 wt. %solids. The treatment consisted of admixing with the oil: 2000 ppm ofthe admixture of demulsifier and surfactant in 4:1 ratio with 25 vol.%of water. After 2 hours of settling at 150° F., the separated oil phasehad a solids content of only 0.6 wt. %.

In another test, the complete process described by reference to FIG. 2was demonstrated on a large specimen of oil taken from the pilot plant.The oil used was made up of heavy, middle, light oil, and gas naphtha intheir production ratios as characterized in Tables II-A and II-B underRun 9, the oil having a solids content of 5.5 wt. %.

The first step treatment consisted of mixing this oil in a tankmaintained at 110° F. with 2000 ppm of the admixture of demulsifier andsurfactant in 4:1 ratio, and 15 wt. % of water. After settling for 24hours, the separated oil phase contained 0.7 wt. % solids and 0.2%water.

The second step treatment consisted of mixing the oil from the firststep with an additional 30 ppm of the disclosed admixture of surfactantand demulsifier and 5 vol. % water, and emulsifying same by passing theadmixture through a mixing valve set at 7 psi. The total admixture wasthen passed into an electrostatic coalescer (Howe Baker) of conventionaldesign operated at 250° F. (other conditions as in Examples 1-6). Theoil phase from the coalescer contained only 0.03 wt. % solids and 0.1vol. % water. The water phase from the coalescer contained only solids,there being no oil present.

It is apparent that various modifications and changes can be madewithout departing the spirit and scope of the present invention.

Having described the invention, what is claimed is:
 1. In a process fordedusting oils characterized as unconventional whole heavy petroleumcrudes, heavy petroleum crude fractions and residua, syncrudes andsyncrude fractions which contain finely divided solids, water beingadmixed with said oil and the water and oil emulsified, and the emulsionthen separated in an electrostatic coalescer to produce asolids-containing aqueous phase, and a clean oil phase which is drawnoff and recovered, the improvement which comprises admixing with saidoil and water to form said emulsion from about 10 parts to about 5000parts, per million parts by volume of oil, of a compound useful as asurfactant, which comprises an ester characterized as follows: ##STR6##where R₁, R₂, R₃, and R₄ are selected from (a) ethoxy or propoxy groups,or mixed ethoxy and propoxy groups, and(b) the dehydroxylated residue ofa fatty acid molecule, or moiety represented by the formula ##STR7##where R is a straight-chain hydrocarbon moiety which can be substitutedor unsubstituted, saturated or unsaturated, and where unsaturated cancontain conjugated or unconjugated double bonds, and at least one and upto three of R₁, R₂, R₃, and R₄ is ethoxy, propoxy, or mixed ethoxy andpropoxy groups.
 2. The process of claim 1 wherein at least one and up tothree of R₁, R₂, R₃ and R₄ is the dehydroxylated residue of the fattyacid molecule represented by the formula ##STR8##
 3. The process ofclaim 2 wherein the hydrocarbon moiety of the fatty acid moleculerepresented by the formula ##STR9## contains from about 6 to about 30carbon atoms.
 4. The process of claim 3 wherein the hydrocarbon moietyof the fatty acid molecule represented by the formula ##STR10## containsfrom about 8 to about 20 carbon atoms.
 5. The process of claim 1 whereinthe molecular species is an admixture of compounds, and the molecularaverage of the admixture contains about three of the ethoxy, propoxy ormixed ethoxy and propoxy groups, and about one fatty acid group.
 6. Theprocess of claim 1 wherein, in an individual R₁, R₂, R₃ and R₄ group,the number of ethoxy, propoxy or mixed ethoxy and propoxy groups rangesfrom 1 to about
 50. 7. The process of claim 6 wherein, in an individualR₁, R₂, R₃ and R₄ group, the number of ethoxy, propoxy or mixed ethoxyand propoxy groups ranges from about 2 to about
 10. 8. The process ofclaim 7 wherein, in the molecule, the sum total of the ethoxy, propoxyor mixed ethoxy/propoxy groups ranges from about 5 to about
 50. 9. Theprocess of claim 6 wherein, in an individual R₁, R₂, R₃, and R₄ group,the number of ethoxy, propoxy or mixed ethoxy and propoxy groups rangesfrom 1 to about
 25. 10. The process of claim 1 wherein, in the molecule,the sum total of the ethoxy, propoxy or mixed ethoxy/propoxy groupsranges from about 10 to about
 30. 11. The process of claim 1 wherein, inan individual R₁, R₂, R₃ and R₄ group, the number of ethoxy, propoxy ormixed ethoxy and propoxy groups ranges from about 1 to about 50, andwherein, in the molecule, the sum total of the ethoxy, propoxy or mixedethoxy and propoxy groups ranges from about 5 to about
 50. 12. Theprocess of claim 1 wherein, in an individual R₁, R₂, R₃ and R₄ group,the number of ethoxy, propoxy or mixed ethoxy and propoxy groups rangesfrom about 2 to about 10, and wherein in the molecule the sum total ofthe ethoxy, propoxy or mixed ethoxy/propoxy groups ranges from about 10to about 30.